canvas.clearrect is not a function,以下是我的详细回答: 确认canvas.clearrect是否为正确的API调用: canvas.clearrect 不是一个正确的 API 调用。正确的 API 应该是 clearRect,注意 Rect 的大小写以及它是驼峰命名法。 给出正确的清除canvas矩形区域的API: 正确的 API 是 clearRect(x, y, width, height),...
clearRect(x, y, w, h) - clears all pixels on the canvas in the given rectangle to transparent blackTo draw a rectangle, the easiest way is to use fillRect. This draws a rectangle on the canvas using the current fillStyle. Here's how to create a black rectangle.This...
# CanvasContext.clearRect(number x, number y, number width, number height)清除画布上在该矩形区域内的内容# CanvasContext.fill()对当前路径中的内容进行填充。默认的填充色为黑色。# CanvasContext.stroke()画出当前路径的边框。默认颜色色为黑色。
context.fillRect((i*2+1) * GAP, 0, GAP, 480); } 1.4 只重绘变化部分而不是全部重绘 4.RENDER SCREEN DIFFERENCES ONLY, NOT THE WHOLE NEW STATE 在屏幕上绘制较少的东西要比绘制大量的东西节省资源。重绘时如果只有少量的差异你可以通过仅仅重绘差异部分来获得显著的性能提升。换句话说,不要在重绘前清...
(default is "return true") clear(x, y, w, h); // canvas clearRect function push(); // canvas save function pop(); // canvas restore function translate(x, y); // canvas translate function rotate(degree); // canvas rotate function clip(); // ctx.clipPath() function scale(p); ...
ctx.clearRect(0,0,489,34); result_base64_src.value=""}//绘制图像 图片对象,x位置,y位置letimg=newImage() img.src=option.img//图片载入数据后再进行绘制img.onload=()=>{// 第一种情况:当图片的高度height>34px//获取图片的高度和宽度://将图片的按照原有的比例进行缩放 为height:34letoriginal...
fillRect(0,0, width, height) ctx.fillStyle = 'white' ctx.arc(width/2, height/2, 40, 0, 2 * Math.PI) ctx.fill() } async function render(){ // save to a multi-page PDF file await canvas.saveAs("all-pages.pdf") // save to files named `page-01.png`, `page-02.png`, ...
voidBaseRenderingContext2D::clearRect(doublex, doubley, doublewidth, doubleheight, boolfor_reset) Webgl初始参数: View Code surface 与 canvas示例: C:\dev\skia_source\modules\canvaskit\npm_build\multicanvas.html C:\dev\skia_source\modules\canvaskit\npm_build\types\canvaskit-wasm-tests.ts ...
Example 2-1. Basic rectangles function drawScreen() { context.fillStyle = '#000000'; context.strokeStyle = '#ff00ff'; context.lineWidth = 2; context.fillRect(10,10,40,40); context.strokeRect(0, 0,60,60); context.clearRect(20,20,20,20); } Figure 2-1. Basic rectangles ...
void clearRect(in float x, in float y, in float w, in float h); void fillRect(in float x, in float y, in float w, in float h); void strokeRect(in float x, in float y, in float w, in float h); // Complex shapes (paths)API ...